1. Field of the Invention
This invention relates to universal joint and shaft assemblies and methods of making same. The invention has been developed primarily for application to assemblies of this kind of use in motor road or other automotive vehicles for transmitting the drive from the prime mover to driving wheels either at the rear or at the front of the vehicle.
2. Description of Prior Art.
The generally conventional practice used hitherto in the manufacture of universal joint and shaft assemblies has been to make the shaft member and the universal joint member to which it is to be connected of a ferrous metal such as steel or cast iron, and to join these members to each other by welding.
The use of welding for this purpose does represent a design constraint by reason of the fact that the materials employed for the two members must then necessarily be selected to have welding compatability. Further, the use of a ferrous metal for the manufacture of the universal joint member (or indeed the universal joint as a whole) is consequent upon the necessity in a large number of applications, such as propeller shaft and universal joint assemblies for motor vehicles, to comply with strength requirements which have to be met but the use of steel for the shaft brings an appreciable weight penalty. It has been proposed to use a fibre reinforced synthetic resin material for the shaft, but such a material cannot be welded to a metal joint member.